For NXP (founded by Philips) LPC2220 — Pulse Width Modulator
Simulation support for this peripheral or feature is comprised of:
- Dialog boxes which display and allow you to change peripheral configuration.
These simulation capabilities are described below.
Pulse Width Modulator Dialog
The Pulse Width Modulator dialog configures Pulse Width Modulator
(PWM) simulation. When configured for PWM mode, the Timers (0 or 1)
provide a basis for PWM outputs. Pulse period, pulse width, single
and double edge controlled outputs are supported.
PR (PWM Prescaler Register) contains the number of times
(minus 1) PCLK must cycle before incrementing the PWM Timer Counter
PC (PWM Prescaler Counter) contains the incrementing
counter value. When this value equals the PR value plus 1, the PWM
Timer Counter (TC) is incremented.
TCR (PWM Timer Control Register) contains the Counter
Enable, Counter Reset and the PWM Enable control bits.
TC (PWM Timer Counter) contains the current value of the
incrementing PWM Timer. When the Prescaler Counter (PC) reaches the
Prescaler Register (PR) value plus 1, this counter is
Counter Enable is set to enable the PWM Timer Counter
and PWM Prescale Counter.
Reset is set to reset the PWM Timer Counter and the PWM
Prescale Counter to zero.
PWM Enable enables PWM mode. In this mode, writing to a
Match Register does not affect the the match result until a
corresponding bit in Latch Enable Register (LER) is set followed by
a PWM Match event.
IR (Interrupt Register) contains the interrupt flags for
PWM Match Channels 0-6. An interrupt flag is set when an interrupt
occurs for that channel (MRx Interrupt).
Match Channels The Match Channel group allows simulation of
6 single-edge controlled or 3 double-edge controlled PWM outputs. You
may modify the seven Match Channels to configure these PWM outputs to
suit your requirements. Selected Channel
MRx (Match Register x) contains the value to be compared
to the Timer Counter (TC) value. When equal, a Match event
Match x Latch is set to allow the last value written to
a Match Register x to become active on the next timer reset.
MRx Interrupt (Match Register x Interrupt) is set when a
interrupt occurs for Match Channel 0-6
Interrupt on MRx is set to allow an interrupt to occur
on Match Channel 0-6 when Match Register x (MRx) equals the Timer
Counter (TC) value.
Reset on MRx is set to reset the Timer Counter (TC) when
the Match Register (MRx) equals the Timer Counter (TC) value.
Stop on MRx is set to stop the Timer Counter (TC) and
Prescaler Register (PC) when the Match Register (MRx) equals the
Timer Counter (TC) value. This condition also sets the Timer
Counter Register (TCR) to zero.
EMCx (External Match Control 0-3) can be set to Clear
(set External output low), Set (set External output high), Toggle
(reverse the state of the External output) or do nothing.
External Match x is set to connect pin Mx to the output
of MAT0/1 and perform the selected Match Control (EMCx) on that pin
when the the Match x event occurs. Note: If Timer 0 is used,
External Match 3 cannot be connected to a device pin.
MCR (PWM Match Control Register) contains the Interrupt,
Reset and Stop bits that control the selected Match Channel.
EMR (External Match Register) contains the External
Match bits and the External Match Control settings.
LER (Latch Enable Register) contains the Match x Latch
bits for each Match Channel.
PCR (PWM Control Register) contains the bits that enable
PWM outputs 0-6 and select single-edge or double-edge control for